The influence of ply orientation on the resistance to mode I delamination of multidirectional composite laminates can be assessed by Double Cantilever Beam (DCB) tests. However, one difficulty is to ...uncouple the global and local effects due to the stacking sequence, which is necessary for a conclusive analysis. In the present work six multidirectional DCB specimens were designed so as to obtain an uncoupled fully isotropic elastic behavior, with the same properties for the entire laminate and the two sub laminates separated by the pre-crack at mid-plane. These specimens have different ply orientations, but their elastic properties are exactly the same. Hence differences in mode I delamination behavior are only due to local fiber orientation effects. Experimental results show that the measured toughness at the crack initiation decreases with both adjacent and sub-adjacent ply angles. During the crack propagation, the plateau value of the R-curve increases with the ply angle of adjacent plies.
It is increasingly recognized that soil microbes have the ability to decompose old recalcitrant soil organic matter (SOM) by using fresh carbon as a source of energy, a phenomena called priming ...effect (PE). However, efforts to determine the consequences of this PE for soil carbon and nitrogen dynamics are in their early stage. Moreover, little is known about the microbial populations involved. Here we explore the consequences of PE for SOM dynamics and mineral nitrogen availability in a soil incubation experiment (161 days), combining the supply of dual-labeled (
13C and
14C) cellulose and mineral nutrients. The microbial groups involved in PE were investigated using molecular fingerprinting techniques (FAMEs and B- and F-ARISA). We show that mean residence time of SOM pool controlled by the PE decreased from 3130 years in the subsoil, where the availability of fresh carbon is very low, to 17–39 years in the surface layer. This result suggests that the decomposition of this recalcitrant soil C pool is strictly dependent on the presence of fresh C and is not an energetically viable mean of accessing C for soil microbes. We also suggest that fungi are the predominant actors of cellulose decomposition and induced PE and they adjust their degradation activity to nutrient availability. The predominant role of fungi can be explained by their ability to grow as mycelium which allows them to explore soil space and mine large reserve of SOM. Finally, our results support the existence of a bank mechanism that regulates nutrient and carbon sequestration in soil: PE is low when nutrient availability is high, allowing sequestration of nutrients and carbon; in contrast, microbes release nutrients from SOM when nutrient availability is low. This bank mechanism may help to synchronize the availability of soluble nutrients to plant requirement and contribute to long-term SOM accumulation in ecosystems.
•Penicillin G is used in porcine production.•Sub-inhibitory concentrations of penicillin G induce biofilm of A. pleuropneumoniae.•Changes in the biofilm matrix components were observed after exposure ...to sub-inhibitory concentrations of penicillin G.•Sub-inhibitory concentrations of penicillin G appear to induce a cell envelope stress sensed by the CpxRA system.
Actinobacillus pleuropneumoniae is a Gram-negative bacterium and causative agent of porcine pleuropneumonia. This is a highly contagious disease that causes important economic losses to the swine industry worldwide. Penicillins are extensively used in swine production and these antibiotics are associated with high systemic clearance and low oral bioavailability. This may expose A. pleuropneumoniae to sub-inhibitory concentrations of penicillin G when the antibiotic is administered orally. Our goal was to evaluate the effect of sub-minimum inhibitory concentration (MIC) of penicillin G on the biofilm formation of A. pleuropneumoniae. Biofilm production of 13 field isolates from serotypes 1, 5a, 7 and 15 was tested in the presence of sub-MIC of penicillin G using a polystyrene microtiter plate assay. Using microscopy techniques and enzymatic digestion, biofilm architecture and composition were also characterized after exposure to sub-MIC of penicillin G. Sub-MIC of penicillin G significantly induced biofilm formation of nine isolates. The penicillin G-induced biofilms contained more poly-N-acetyl-d-glucosamine (PGA), extracellular DNA and proteins when compared to control biofilms grown without penicillin G. Additionally, penicillin G-induced biofilms were sensitive to DNase which was not observed with the untreated controls. Furthermore, sub-MIC of penicillin G up-regulated the expression of pgaA, which encodes a protein involved in PGA synthesis, and the genes encoding the envelope-stress sensing two-component regulatory system CpxRA. In conclusion, sub-MICs of penicillin G significantly induce biofilm formation and this is likely the result of a cell envelope stress sensed by the CpxRA system resulting in an increased production of PGA and other matrix components.
► The corrosion rates of steel in two soils with different resistivity are compared. ► The influence of soil resistivity is negligible. ► The behaviour of steel in soil under cathodic protection is ...studied. ► Residual corrosion rates under cathodic protection are estimated via voltammetry. ► The methodology presented here could be used to monitor cathodic protection.
Steel coupons were buried in soil boxes for 2.5months, with or without cathodic protection. A soil from the field was used and moistened by demineralized water or 5gL−1 Na2SO4 solution. Instantaneous corrosion rates were deduced from voltammetry experiments while average values were obtained by weight loss measurements. A detailed analysis of the polarization curves led to an estimation of residual corrosion rates (τrc) of coupons under cathodic protection. This residual phenomenon could be followed with time and it was observed that τrc decreased down to ∼10μmyr−1. Cathodic protection could be optimised with this methodology.
Robotic thyroidectomy (RT) has been reported to achieve satisfactory results. However, its long-term oncological results have not been validated. The use of RT to treat thyroid cancer comprises ...specific risks that are not encountered with open thyroidectomy (OT).
We report the case of a patient operated by two-stage RT for stage pT3a follicular carcinoma, followed by tumour seeding along the incision despite adjuvant Iodine-131 therapy and external beam radiotherapy.
This case illustrates the limitations and insufficient perspective of RT for thyroid cancer, with the recent discovery of a risk of tumour seeding along the incision. Rigorous patient selection should help to avoid this risk of tumour seeding.
The central aim of conservation biology is to understand and mitigate the effects of human activities on biodiversity. To successfully achieve this objective, researchers must take an ...interdisciplinary approach that fully considers the effects, both direct and indirect, of anthropogenic disturbances on wildlife physiology and health. A recent surge in research has revealed that host-associated microbiota-the archaeal, bacterial, fungal and viral communities residing on and inside organisms-profoundly influence animal health, and that these microbial communities can be drastically altered by anthropogenic activities. Therefore, conservation practitioners should consider the disruption of host-associated microbial diversity as a serious threat to wildlife populations. Despite the tremendous potential for microbiome research to improve conservation outcomes, few efforts have been made to truly integrate these fields. In this review, we call for the microbial renaissance of conservation biology, where biodiversity of host-associated microbiota is recognized as an essential component of wildlife management practices. Using evidence from the existing literature, we will examine the known effects of anthropogenic activities on the diversity of host-associated microbial communities and integrate approaches for maintaining microbial diversity to successfully achieve conservation objectives.
Experimental and numerical methods to identify the linear viscoelastic properties of flax fibre reinforced polymer (FFRP) composite are presented in this study. The method relies on the evolution of ...storage modulus and loss factor as observed through the frequency response. Free-free symmetrically guided beams were excited in the dynamic range of 10 Hz to 4 kHz with a swept sine excitation focused around their first modes. A fractional derivative Zener model has been identified to predict the complex moduli. A modified ply constitutive law has been then implemented in a classical laminates theory calculation (CLT) routine. Overall, the Zener model fitted the experimental results well. The storage modulus was not frequency dependant, while the loss factor increased with frequency and reached a maximum value for a fibre orientation of 70°. The damping of FFRP was, respectively, 5 and 2 times higher than for equivalent carbon and glass fibres reinforced epoxy composites.
Witches and demons Fontaine, Jean La
2016., 20160401, 2016, 2016-04-30, Letnik:
10
eBook
Devil worship, black magic, and witchcraft have long captivated anthropologists as well as the general public. In this volume, Jean La Fontaine explores the intersection of expert and lay ...understandings of evil and the cultural forms that evil assumes. The chapters touch on public scares about devil-worship, misconceptions about human sacrifice and the use of body parts in healing practices, and mistaken accusations of children practicing witchcraft. Together, these cases demonstrate that comparison is a powerful method of cultural understanding, but warns of the dangers and mistaken conclusions that untrained ideas about other ways of life can lead to.
Following intergroup conflict, reconciliation efforts most often focus on relationships among people. Though human-centric approaches are valuable, we propose people's engagement in reconciliation is ...also related to their attitudes toward the broader natural world. With a sample of 233 undergraduate non-Indigenous Canadian students who completed an online survey, we investigated the relationships among connectedness to nature, animal-human continuity, moral expansiveness, and support for reconciliation. All variables correlated positively, though the correlation between animal-human continuity and support for reconciliation was not significant. As well, age positively and significantly correlated with connectedness to nature, whereas gender (coded 0 = male, 1 = female) positively and significantly correlated with animal-human continuity, moral expansiveness, and support for reconciliation. To better understand how connectedness to nature and animal-human continuity related to moral expansiveness and support for reconciliation, we conducted mediation analyses. Participants who felt more connected to nature had more positive attitudes toward reconciliation, because they were more morally expansive. A similar pattern emerged for animal-human continuity, though only for women. These findings imply that strengthening peoples' connection to nature or beliefs about how humans and other animals are similar, and consequently extending peoples' circles of moral concern, may increase support for reconciliation.
Après un conflit entre groupes, les efforts de réconciliation sont le plus souvent centrés sur les relations entre les individus. Si les démarches centrées sur les humains sont valables, nous proposons que l'engagement des individus envers la réconciliation est aussi relié à leurs attitudes à l'égard de l'ensemble du monde naturel. Au moyen d'un échantillon de 233 étudiants canadiens non autochtones inscrits à un programme de premier cycle à l'université ayant répondu à un questionnaire en ligne, nous avons étudié les rapports entre la connexité avec la nature, la continuité animal-humain, la capacité d'expansion morale et l'appui à la réconciliation. Toutes les variables corrélaient positivement les unes avec les autres, mais la corrélation entre la continuité animal-humain et l'appui à la réconciliation n'était pas significative. En outre, l'âge corrélait positivement et de façon significative avec la connexité avec la nature, tandis que le genre (codé 0 = homme; 1 = femme) corrélait positivement et de façon significative avec la continuité animal-humain, la capacité d'expansion morale et l'appui à la réconciliation. Nous avons effectué des analyses de la médiation pour mieux comprendre en quoi la connexité avec la nature et la continuité animal-humain étaient reliées à la capacité d'expansion morale et à l'appui à la réconciliation. Les participants qui se sentaient plus étroitement liés à la nature avaient des attitudes plus positives à l'égard de la réconciliation parce qu'ils avaient une plus grande capacité d'expansion morale. Une tendance semblable s'est dégagée pour la continuité animal-humain, mais pour les femmes seulement. Ces résultats indiquent que le renforcement des liens des individus avec la nature ou de leurs croyances au sujet de la similitude des humains et d'autres animaux, et conséquemment l'élargissement des sphères de préoccupation morale des individus, peut accroître le soutien à l'égard de la réconciliation.
Public Significance Statement
We studied non-Indigenous undergraduate university students' attitudes about the natural world and support for reconciliation with Indigenous Peoples in Canada. Those who felt more connected to nature and viewed people and animals as more similar than different were more supportive of reconciliation, in part because they think more entities (e.g., people, animals, plants) are worthy of moral concern. Our research also implies possible ways to increase support for reconciliation: Exposure to the natural world and education about how humans and animals are similar.
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